package com.myblog.utils;


import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

/**
 * <p>验证码</p>
 * <p>2019-8-20</p>
 * <p>LiHuaJie</p>
 */
public class VerifyUtils {

    //验证码字符个数
    private static int codeCount = 4;
    //验证码干扰线数
    private static int lineCount = 168;

    //验证码字符集
    private static final char MAPTABLE[] = {
            '0','1','2','3','4','5','6','7','8','9',
            'a','b','c','d','e','f','g','h','i','j','k','l','m','n',
            'o','p','q','r','s','t','u','v','w','x','y','z',
            'O','P','Q','R','S','T','U','V','W','X','Y','Z'
    };

    /**
     * 给定防卫获取随机颜色
     * @param fc
     * @param bc
     * @return
     */
    static Color getRandColor(int fc, int bc){
        Random random = new Random();
        if (fc > 255) fc = 255;
        if (bc > 255) bc = 255;
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r,g,b);
    }

    /**
     * 生成随机验证码及图片
     * @param width
     * @param height
     * @param os
     * @return
     */
    public static Map<String,Object> getImageCode(int width,int height, OutputStream os){
        Map<String,Object> returnMap = new HashMap<String,Object>();
        if (width <= 0) width = 60;
        if (height <= 0) height = 20;
        BufferedImage image = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);
        //获取图形上下文
        Graphics g = image.getGraphics();
        //生成随机类
        Random random = new Random();
        //设定背景色
        g.setColor(getRandColor(200,250));
        g.fillRect(0,0,width,height);
        //设定字体(新罗马字体)
        g.setFont(new Font("Times New Roman",Font.PLAIN,18));
        //随机生成168条干扰线，使图像中的认证码不易被其他程序探测到
        g.setColor(getRandColor(160,200));
        for (int i = 0; i < lineCount; i++){
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x,y,x+xl,y+yl);
        }
        //取随机产生的码
        String strEnsure = "";
        //产生4位验证码
        for (int i = 0; i < codeCount; i++){
            strEnsure += MAPTABLE[(int)(MAPTABLE.length * Math.random())];
            //将认证码显示到图像中
            g.setColor(new Color(20 + random.nextInt(110),20 + random.nextInt(110),20 + random.nextInt(110)));
            //直接生成
            String str = strEnsure.substring(i, i+1);
            //设置随机码再背景图片上的位置
            g.drawString(str,13 * i + 20, 25);
        }
        //释放图形上下文
        g.dispose();
        returnMap.put("image",image);
        returnMap.put("strEnsure",strEnsure);
        return returnMap;
    }





}
